Cockroaches Invading New Zealand Homes
There has been a recent surge in cockroach infestations in the warmer parts of New Zealand. Over the last couple of
months, a time when sales normally slacken off as colder weather slows cockroaches down, sales of pest control products
specifically designed to control cockroaches have increased to record levels.
“This year is different,” says Kiwicare pest expert David Brittain. “It is likely that the warm summer followed by an
extended mild and damp autumn has seen numbers swell, particularly in the North Island and top of the South. Now the
recent high rainfall is driving cockroaches to seek shelter and warmth in our increasingly well heated homes.”
Cockroaches are large resilient beetles often referred to as the creatures that will ‘inherit the Earth’ in the event of
a nuclear catastrophe. This may or may not be true, but they can be difficult to eradicate from buildings once they
become established.
Cockroaches are implicated in transmission of disease. They will often move from drains, bins and decaying matter onto
food and food preparation surfaces, transferring bacteria and viruses as they go. “Remove and cover all food so that
cockroaches cannot contaminate it,” says David. Some of the cockroaches entering homes and other buildings are likely to
be the smaller native Bush Cockroach which is less likely to cause harm, but many infestations are the common pest
species; German, American and Gisborne.
The particular difficulty in eradicating cockroach infestations is that cockroaches lay eggs and egg cases in cracks,
crevices and areas that are hard to reach with insecticides. The eggs can hatch out weeks and months after treatment,
when it appears that the cockroaches have been eliminated.
“Bait, Barrier, Monitor,” says David. “Use cockroach bait in many small amounts where cockroaches have been seen.
Follow baiting with safe long lasting surface insecticide such as permethrin or deltamethrin to treat the cracks and
crevices where cockroaches hide during the day. Pay particular attention to skirting, areas underneath cupboards and
sinks, and other warm moist dark spaces.”
If your property has had an infestation in the past then it is likely to be susceptible to infestation again. Non-toxic
cockroach traps are an excellent way to monitor for infestations. They can be safely used in sensitive areas like
kitchens and pantries. The traps can be checked regularly and if cockroaches are found an elimination treatment can be
carried out before they have time to become established.
Also, think about how the cockroaches may have found their way inside. In many warmer and humid parts of New Zealand the
cockroaches can survive outside, so consider placing a chemical barrier around the house and other buildings. This can
be a barrier of insecticide such as those mentioned previously or slow release garden insecticide prills sprinkled in
ring around the building.
You can do it yourself with products available in hardware stores or if you don’t feel like controlling the cockroaches
yourself you can call in a professional pest control company with technicians registered with the Pest Management
Association of NZ (PMANZ).
ENDS